1. Field of the Invention
This invention relates broadly to surgical methods. More particularly, this invention relates to a method for performing coronary artery bypass surgery.
2. State of the Art
Substantially all coronary artery bypass (CAB) procedures are performed via an open chest method. In the procedure, the chest is opened through an, incision in the middle of the chest, called a sternotomy, and the ribs are retracted and held stably open with a retractor. This provides a sufficient amount of access to the heart. The heart is then arrested and the blood flow is rerouted through a heart-lung machine. The bypass procedure is then performed, and once complete, the heart is then restarted and blood is permitted to flow through the xe2x80x9cbypassxe2x80x9d. While this procedure is the norm, it is far from desirable. First, arresting the heart is a dangerous procedure and can lead to serious complications and even death. Second, the procedure requires a sternotomy, which is painful and traumatic. Because of this incision the recovery time is relatively long and the patient is left with a permanent large scar.
More recently, some surgeons have performed coronary artery bypass surgery on a beating heart. The chest is opened via a sternotomy and retracted. Using a device called a heart stabilizer, the surgical site on the heart is essentially immobilized for suturing. The heart stabilizer is typically anchored to the retractors which are in turn anchored to the walls of the chest at the site of the incision. Direct access to the surgical site as well as immobilization of the surgical site are key to the surgery. These factors allow the surgeon to perform a suture or other operation with precision. While the methodology is effective and eliminates the potential complications of arresting the heart, the drawbacks associated with the sternotomy remain.
It has recently been proposed by others to perform a closed chest bypass procedure on the beating heart. However, the proposal has not been followed by any concrete directions on how to satisfactorily perform the procedure. In addition, the inventors of the present application have recognized that the closed chest procedure has a number of hurdles to overcome. First, it is necessary to stabilize the heart such that the location requiring the bypass does not significantly move during the procedure. Second, while open chest procedure are accompanied by a retractor and instrument supporting framework, in a closed chest procedure, there is no such framework for holding the instruments required for the procedure. In addition, there is no suitable stable port device adapted to securely support instruments passing therethrough. Third, when performing any surgery through a port, the instruments used to work at the surgical site are relatively long compared to open chest instruments. The distance from the surgeons""s hand to the tip of the instrument where the work is being performed can be many times greater than in conventional surgery. This increase in length amplifies normal hand tremor and any errors in motion.
It is therefore an object of the invention to provide a less traumatic instrument access to the surgical site.
It is another object of the invention to provide a port device which is easy to insert into the body.
It is a further object of the invention to provide a port device with a high degree of stability.
It is an additional object of the invention to provide a heart stabilizer which can be inserted through the port device and which is adapted to stabilize a portion of a beating heart such that coronary artery bypass surgery can be performed on the portion of the heart.
It is also an additional object of the invention to provide a heart stabilizer which can be manipulated via a proximal handle external of the port device.
It is still another object of the invention to provide an instrument stabilization system which minimizes unwanted motion of the tips of instrument performing the procedure.
It is still a further object of the invention to provide an instrument stabilization system which can be coupled to the port device.
It is yet another object of the invention to provide a system of components which cohesively operates together to facilitate port off-pump coronary artery bypass surgery on a beating heart.
It is yet a further object of the invention to provide a method of performing port off-pump coronary artery bypass surgery on a beating heart.
In accord with these objects, which will be discussed in detail below, a system for performing port off-pump beating heart coronary artery bypass surgery is provided. The system includes three primary subsystems: a port device, a heart stabilizer, and an instrument stabilizer.
The port device is insertable between the ribs of the patient and functions as an entry way for each instrument necessary for the procedure, e.g., optics, graspers, needle holders, suction/irrigation tubes, stabilizers. According to a preferred aspect of the invention, the port device includes a tubular body having proximal and distal portions and intended to be inserted through a pair of ribs in a chest wall of a patient. The proximal portion of the tubular body includes a plurality of thread grooves extending at least partially about a circumference of the body as well as a means to permit the heart stabilizer, the instrument stabilizer, or another device to be releasably secured to the port. The distal portion of the tubular body is coupled to a swivel adapted to be moved between a first orientation in which the swivel extends in substantially a same direction as the body, and a second orientation at an angle relative to, and preferably substantially perpendicular to, the first orientation.
According to certain embodiments of the port device, a washer is positioned on the body between the swivel and the proximal portion of the body, and a locknut is threadably engaged in the thread grooves. When the tubular body is inserted between two ribs in the chest wall of the patient, the swivel is then opened into the second orientation and the washer is moved along the body to position the chest wall between the swivel and the washer. The locknut is then tightened about the body to clamp the washer against the chest wall and stably secure the tubular body within the chest wall.
According to other embodiments of the port device, a platform movable along the length of the port body includes adjustable legs and feet. The legs are adjusted such that the feet contact the chest wall and clamp the chest wall between the feet and the swivel. In addition, the legs may be adjusted to provide the body in a desired angle relative to the chest wall. According to preferred aspects of these embodiments of the port device, the platform may be ratcheted relative to the port body and the feet may be ratcheted relative to the platform to permit rapid adjustment of the port relative to the patient. In addition, preferably three legs are provided to aid in stability of the port on the body of the patient.
According to various aspects of the several embodiments of the port, the port may include a thread system adapted to permit quick locking of the locknut against the washer or the platform along the body, one or two swivels, and/or a ball joint permitting angular orientation of the port to permit the port to be directed toward a desired location such as the surgical site. In addition, the swivel or swivels may be spring biased to move from the first orientation to the second orientation, or an introducer device may be provided to mechanically move the swivel or swivels between the first and second orientations.
The heart stabilizer preferably includes a shaft and two jointed arms coupled to a distal end of the shaft. At the end of each arm is a rotatable foot adapted to be angled relative to the heart wall contour and apply pressure against the wall of the heart to effectively eliminate motion of the heart wall between the feet. The stabilizer is adapted to provide a stabilized area sufficiently large to allow an accurate anastomosis to be performed. According to preferred aspects of the invention, the stabilizer is particularly adapted to be collapsible (foldable) to be inserted through the port device and locked longitudinally relative thereto. The stabilizer is also preferably adapted to be automatically deployed into its final configuration by release of a lock actuated at a proximal portion of the stabilizer extending outside the port. In addition, the stabilizer is adapted to automatically fold when being pulled back through the port.
According to various embodiments of the heart stabilizer, the feet of the stabilizer may be further adapted to facilitate immobilization of the heart wall between the feet. In addition to compressive forces, the feet may apply suction, chemical agents, electrical current, or thermal cooling to enhance the heart wall immobilization.
According to another aspect of the invention, the instrument stabilizer is adapted to minimize unwanted motion at the distal end of a surgical instrument extending through the instrument stabilizer by applying a biasing force to the tip of the instrument. The instrument stabilizer may be coupled to a port or may be coupled directly to a patient, e.g., with sutures. According to a preferred embodiment, the instrument stabilizer preferably includes a cannula (tubular member) through which an instrument can extend, and a preferably distal contact element, e.g., an O-ring or a tapered diameter of the cannula, adapted to be in a close fit about the instrument and which provides proximal and distal stabilization. The instrument stabilizer also includes a proximal housing that includes a mechanism which applies a stabilizing force to the tubular member for movements transverse to the axis of the cannula. The mechanism which applies the force may be, by way of example, one or more of elastic bands, springs, struts, etc. When the surgical instrument is extended through the cannula and contacts the contact element, movement of the cannula and consequently the surgical instrument is damped by the stabilization force on the cannula. According to another embodiment, a mechanism which applies a stabilization force may be attached to a shaft of another instrument, e.g., the shaft of the heart stabilizer. According to yet another embodiment, the cannula is provided with a valve to permit the instrument stabilizer to be used for surgical procedures requiring insufflation of the body cavity in which the instrument stabilizer is inserted.
A stabilizer swivel may be used with an instrument stabilizer to angularly direct the cannula of the instrument stabilizer relative to the body of the patient. The stabilizer swivel includes upper and lower wedges rotatably coupled to each. Each wedge includes an opening through which the cannula may be extended. Relative rotational configurations of the wedges operate to orient the opening of the upper wedge relative to the lower wedge and the surface on which the lower wedge is seated.
The above-described components together define a surgical system for performing port off-pump beating heart coronary artery bypass surgery. According to a preferred method which utilizes the system, a port device is stably positioned, e.g. clamped, in the chest wall and directed as necessary for operation on the heart wall. A heart stabilizer is coupled to the port, and operated to apply a compressive force against the heart wall surrounding a location of the required bypass such that the location is substantially immobilized. An instrument stabilizer is inserted through a puncture hole in the chest cavity, and the distal tip of the cannula of the stabilizer is located adjacent to the surgical site. A first surgical instrument, e.g., a scalpel or needle holder, is passed through the cannula and operated to perform at least a portion of the procedure. If other surgical instruments are required, the first instrument may be removed and other instruments may be extended therethrough. Alternatively, an instrument stabilizer may be provided for each instrument. Once the bypass procedure is complete, the instruments and instrument stabilizers are removed from the locus of the surgery, and the heart stabilizer is also removed through its port. Then, the clamping forces on the port is loosened and the port is withdrawn from the chest wall. Finally, the incision and puncture holes in which the port and instrument stabilizer were located are closed. This method eliminates the need for many open heart procedures, as well as the need to stop the heart.
Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.